This invention relates to an improved inhalation device that indicates the amount of medicament in an associated dispenser and, optionally, the number of doses dispensed from an associated dispenser over a predetermined period.
It is well known to treat patients with medicaments that are dispensed from an aerosol dispenser. The dispenser has become generally standardized and thus is usually in the form of a cylindrical container, usually comprised of metal, that has a proximal end and a distal end. A compression actuated, fixed dose metering and dispensing valve is axially disposed at the proximal end of the container in a constricted neck region. The valve includes an axially (relative to the container) projecting stem tube through which a single dose of aerosol medicament is dispensed in response to each valve-actuating compression of the valve.
The aerosol medication in such a container (or dispenser) can be conveniently administered to a patient by means of a prior art inhalation device that typically comprises a tubular housing or sleeve which receives and holds the dispenser and an associated nozzle from which, upon valve actuation, the medication is dispensed. The aerosol dispensers used in such inhalation devices typically are commercially readily available and are sold typically in 100 and 200 dose sizes. The outlet (or dispensing) valve member at the proximate dispenser end can be opened either by depressing the valve member while the dispenser is held stationary or by depressing the dispenser while the valve member is held stationary.
In use, an aerosol dispenser that is placed in the dispenser""s tubular housing has the outlet or dispensing valve resting upon a support or valve seat in the inhalation device. The support communicates with an outlet tube (or channel) that terminates adjacently to the nozzle""s mouthpiece that is usually angled relative to the dispenser housing axis. When used for dispensing medicaments, such as used, for example, in bronchodilation therapy, or the like, the housing is held by the patient in a more or less upright condition with the mouthpiece or nozzle of the inhalation device placed in the mouth of the patient. The distal end of the aerosol container is pressed towards the support to actuate the valve and dispense a dose of medicament from the container which is then inhaled by the patient.
A principal problem with prior art inhalation devices is that they provide no means by which a patient can acquire information concerning either the amount of medicament remaining in an associated dispenser or the number of doses dispensed from an associated dispenser.
Patient compliance with a doctor""s instructions regarding a prescribed aerosol medication is commonly extremely important in the treatment of medical disorders. Although the rate of compliance is higher when the patient must return to the hospital or physician""s office to receive the medication, most drug treatment regimens require the patient to administer the drugs at regular intervals without supervision by hospital personnel, the patient""s physician or other qualified medical personnel. Obviously, the treatment of a medical disorder will be frustrated if the patient does not administer a medication as prescribed. In the past, physicians have had to rely on the patient""s self-interest in his or her own well being to assure that prescribed medications (or, commonly, xe2x80x9cdrugsxe2x80x9d) are properly administered as prescribed or scheduled.
With, for example, anti-anxiety or sedative/hypnotics, such as valium and barbiturates, it is widely recognized that there is a real possibility that the patient will abuse or become dependent on the drug. Past studies have suggested that physicians should avoid the prescription of barbiturates because of the risk of dependence and the high toxicity of the drugs.
Furthermore, many such drugs have a narrow therapeutic dose range and can have severe side effects. It is well recognized that controlling the dosing of these types of drugs is important in mitigating problems with side effects. Many drugs can be extremely expensive (e.g., certain purified peptides and proteins). Controlling patient dosing of these drugs can also have economic benefits.
Dispensers, such as metered dose inhalers, nebulizers and dry powder inhalers, have been used for many years to treat pulmonary disorders such as asthma using aerosol medicaments. A metered dose inhaler typically comprises a canister pressure-fitted with a metering valve, where the canister is filled with an aerosol formulation that includes a drug dissolved or dispersed in a propellant together with a surfactant. Nebulizers are devices which include mechanical or electronic devices (e.g., a piezoelectric element) to atomize a drug suspension positioned in a containment cup. Nebulizers include an air or other gas source to deliver the atomized drug to the patient as a fine mist. Dry powder inhalers include mechanical or electronic devices to produce a fine mist or dispersion from a powdered drug composition.
Patient non-compliance while using inhalation devices has been recognized as a major medical problem. It is generally believed that most patients underdose themselves. Furthermore, over use has been observed in various studies on days following visits to the physician""s office.
It is believed that, if an inhalation device were available for patient use which indicated, relative to an associated dispenser, the amount of medicament dispensed, and preferably also the number of doses administered, then a patient would be much better enabled to watch his own medication and follow a stricter dose regimen. There is a need to improve the patient""s capacity for compliance with prescribed dosing schedules. There is also a need for an inhalation device which can provide some assurance that a patient is not either overdosing or underdosing a prescribed aerosol medicament, as through, for example, circumventing a dosing schedule by not inhaling the medicament.
A further disadvantage arising from use of currently available devices is that the patient cannot determine the amount of medicament in the aerosol container at any given time. In an extreme case, this could mean that the patient, possibly suffering from a severe bronchospasm and needing a dose of medicament, will find that the aerosol container will not dispense a dose because its contents have already been exhausted. There is a need for an inhalation device that avoids this problem.
Previously, in the above identified parent patent application, we have provided a new and very useful inhalation device for use in dispensing a medicament from an aerosol dispenser of the type having an axially disposed, compression actuated fixed dose metering and dispensing valve. The device provides dispenser medicament level information and dispensed dose number information.
Presently, to facilitate the use and application of such a device, we provide new and very useful improvements for association and use with the device.
The present invention relates to an improved inhalation device that is either disposable or reusable. Specifically, the present invention provides an inhalation device that, when used with a medicament dispenser, particularly a dispenser holding a pressurized medicament in aerosol form that is commercially available in a standardized multiple dose size, indicates the level of medicament in the dispenser, and, optionally also, the number of doses dispensed during a predetermined time period.
The present invention thus provides for easy and accurate dosage monitoring of the medicament, either as a single dose or multiple doses.
Examples of use of the inhalation device include delivery of a medicament to a patient""s mouth, nostril, ear canal or eye. The inhalation device can be used to dispense various drugs, including beta-agonists such as albuterol (salbutamol), isoproterenol, ephedrine, epinephrine, salmeterol and terbutaline; corticosteroids such as triamcinolone acetonide, beclomethasone diproprionate, dexamethasone and aldosterone; allergic mediators such as cromcyln sodium; antibiotics; anticholinergics, and the like. Moreover, these drugs when variously formulated and charged into an aerosol dispenser can be dispensed therefrom by the inhalation device whether dissolved or dispersed in a propellant together with a surfactant, a dry powder, or other auxiliary agent.
The inhalation device includes a generally tubular housing defining a lumen that slidably receives and holds a dispenser, a nozzle body at one end of the housing, an advance tube disposed in the housing, a medicament level indicator that slidably extends through a longitudinal slot in the housing and that also slidably associates with a spiral (helical) groove defined in the advance tube, and an advance ring that includes a portion which is slidably located in the advance tube and another portion that is associated with a dispenser.
Optionally but preferably, the inhalation device includes a dose number indicator that utilizes a combination of a window that is preferably defined in the nozzle body and a sequential series of numerical markings that are arranged circumferentially about a portion of the advance tube and that are serially viewable through the window.
Preferably the nozzle body is rotatable relative to the housing, and preferably the nozzle body has an output orifice that is associatable with a replaceable and separatable end cap.
In usage of the inhalation device, the level indicator, by its externally viewable position along the longitudinal slot, indicates a remaining amount of the medicament in the dispenser, while the dose indicator, if present, indicates the number of doses dispensed.
In usage of the inhalator device, to accomplish advance of the level indicator, and of the dose indicator, if present, a radially projecting stud means that is fixed to either the advance ring or the advance tube interconnects the advance ring and the advance tube. An outer end portion of the projecting stud means rests in a serrated (or zigzag) groove defined, correspondingly and reciprocally, in either the advance tube or the advance ring. When the valve of a dispenser that is associated with the inhalation device is actuated, the advance ring moves longitudinally and reciprocatingly. The projecting stud means exerts a camming force against side edge portions of the zigzag groove, and the advance tube is caused to rotate relative to the housing. Concurrently, the level indicator slidably advances both along the helical groove and also along the longitudinal groove. Also concurrently, if the dose indicator is present, a next succeeding dose number moves into viewability in the window.
When the window is in the nozzle body, and the nozzle body is rotatable relative to the housing, dose indicator device can be reset to zero by such rotation so that the number of doses taken in any predetermined time period can be monitored.
One feature of the present invention is that the inhalation device is provided with auxiliary key means for preventing rotation of the advance ring during actuations of the dispenser valve yet allowing longitudinal reciprocal movements of the advance ring.
Another feature of the present invention is that the inhalation device is provided with auxiliary means for accommodating operation of the inhalation device when the medicament level indicator has reached the limit of display capability.
Another feature of the present invention is that the inhalation device is provided with alternative structures and arrangements for the advance ring and the cooperating advance tube.
Another feature of the present invention is that the inhalation device is provided with alternative structures and arrangements for the nozzle.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description and from the accompanying drawings.